1. Field of the Invention
The present invention relates to a thermoplastic resin composition containing various fillers added therein, a production method thereof, and a molded article.
2. Description of Related Art
Thermoplastic resin has been widely used in various fields such as soft or hard films, sheets, flooring materials, and formed articles.
Thermoplastic resin is molded by various methods such as extrusion molding, calender molding, blow molding, and injection molding according to the desired products. In this case, various fillers are added to impart various characteristics. Examples of the fillers include impact strength modifiers, fillers, flame retardants, pigments, and wood flours, papers and fiber used as extenders. Recently, reuse of waste papers and regenerated wood flours has been investigated.
However, when a large amount of filler is added to exert the effect of the fillers, adhesion of degraded resin or fillers in the resin onto lips of a die (die deposit) and migration of fillers in a resin composition onto the metal surface in contact with the resin (plate-out) occur during molding, thereby causing surface irregularities and filler specks and a reduction in impact strength. When the amount of filler is 10 parts by weight based on 100 parts by weight of the thermoplastic resin, these defects are frequently observed.
To solve these problems, processing aids to be added to the thermoplastic resin are widely investigated in Japanese Patent Application, Second Publication No. Hei 6-62826and Japanese Patent Application, Second Publication No. Hei 2-50137 with respect to a polyvinyl chloride resin composition, Japanese Patent Application, First Publication No. Hei 9-208798 with respect to an ABS resin composition, and Japanese Patent Application, First Publication No. Hei 10-87928 with respect to a styrene-based resin composition, and thus calendering roll releasability and retention deterioration of the resin have been improved to some extent.
However, in the case of the molding of a thermoplastic resin and/or a regenerated thermoplastic resin, particularly extrusion molding, calender molding and blow molding of a thermoplastic resin composition containing various fillers such as rubbers, regenerated wood flours, waste papers, flame retardants, and pigments, die deposit and plate-out are not sufficiently suppressed.
Since die deposit and plate-out may deteriorate the appearance of a molded article or make it impossible to carry out the subsequent molding, die lips must be cleaned after terminating the molding operation at fixed intervals and productivity is drastically reduced. There can also be employed a method of suppressing die deposit and plate-out by previously adding lubricants such as acrylic external lubricant, metal soap, and wax to a thermoplastic resin; however, sufficient additional effect is not always exerted.